The present invention is directed to a longitudinally divided sleeve of shrinkable material comprising a closure element along each of the longitudinal edges to form a lock closure. The lock closure comprises one of the elements having a longitudinal locking groove along one longitudinal edge of the divided sleeve and a second closure element being a lock element which mates with the longitudinal locking groove and is provided along the other longitudinal edge.
A method for covering connections of electrical cables and pipes wherein a cladding, which is shrinkable under an influence of heat, is applied over the location of the connection, is then closed by engaging lock elements along the edges and is finally shrunken down onto the enclosed article is disclosed by German OS No. 1,947,057. The closure elements are composed of a longitudinal groove along one longitudinal edge and of a lock element mating with the groove along the second longitudinal edge. Both elements are arranged so that a bead will project outwardly from the cladding. Particularly given high shrinking forces, this has the disadvantage that the closing region is pulled apart so that a longitudinal gap, which will cause a loss of tightness, can occur. The risk also exists that given high shrinking forces, the closure can become undone again since the lock element is engaged in the groove in the same direction as the forces created by the shrinking which are in a circumferential direction. Moreover, the insertion of the lock element in the groove requires greater closing forces if it is to be guaranteed that the closure is also suitable given greater stressing particularly during the shrinking operation.